Conventionally, a driving support apparatus for a vehicle is known, which estimates a likelihood of a collision with another vehicle based on the another vehicle information (hereinafter, referred to as “autonomous sensor information”) which includes a position, a direction, a speed, or the like of the another vehicle measured by an automotive radar, an on-vehicle camera, or the like, and information which includes a position, a travel direction, a speed, or the like of the vehicle (own vehicle), and notifies a driver in advance that the likelihood of the collision if the collision is likely to occur. The driving support apparatus can effectively prevent a vehicle collision at an intersection. Although the automotive radar, the on-vehicle camera, or the like can acquire the autonomous sensor information at a good-visibility intersection, however, they sometimes cannot acquire the autonomous sensor information at a bad-visibility intersection around which there are buildings, trees, or the like.
On the other hand, if each of an own vehicle and another vehicle is equipped with the inter-vehicle communication device, information on the another vehicle such as a position, a direction, a speed, or the like of the another vehicle, that are acquired by a GPS sensor, a speed sensor, or the like, equipped with the another vehicle, can be acquired via the inter-vehicle communication devices. Hereinafter, the information on the another vehicle which is acquired via the inter-vehicle communication devices is referred to as “communicated another vehicle information”.
Accordingly, one of conventional driving support apparatuses (hereinafter, referred to as a “conventional apparatus”) estimates a likelihood of a collision in advance based on not only the autonomous sensor information but also the communicated another vehicle information, and notify the driver of the likelihood of the collision when the collision is likely to occur (for example, refer to Japanese Patent Application Laid-Open (kokai) No. 2008-186416).
Nevertheless, the communicated another vehicle information is generally not so accurate as the autonomous sensor information, since the communicated another vehicle information is information acquired based on the GPS signals. Thus, there may occur a situation where an estimated collision time (in actuality, a time to collision) with respect to a specific another vehicle calculated based on (using) the communicated another vehicle information is slightly different from an estimated collision time with respect to the specific another vehicle calculated based on (using) the autonomous sensor information.
In this case, if the notification (e.g., a display of images, a generation of sounds, or the like) that the “collision is likely to occur” based on respective information is provided, the notified contents are switched over within a short time, and a display of images becomes unstable. This may bother and/or confuse the driver.